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The off topic game thread


John FX

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Simple game, you must not stay on topic. You lose (and will be made a little fun of) if you reply on topic to the last poster. Keep it clean, civil, and nice of course but whatever you do, don`t keep it on topic.

If one poster talks about mun landings the next poster for example must not mention them or refer to them in any way and might post about how whales migrate.

Reaction images are allowed but you must not be reacting to the previous poster and two reaction images in a row is a losing move for the second poster.

I`ll start by not posting on topic, sort of.

57295642.jpg

(I don`t know what the bottom bit means, I hope it is not rude)

 

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RP-1 (alternately, Rocket Propellant-1 or Refined Petroleum-1) is a highly refined form of kerosene outwardly similar to jet fuel, used as rocket fuel. Although having a lower specific impulse than liquid hydrogen (LH2), RP-1 is cheaper, stable at room temperature, far less of an explosion hazard and far denser. RP-1 is significantly more powerful than LH2 by volume. RP-1 also has a fraction of the toxicity and carcinogenic hazards of hydrazine, another room-temperature liquid fuel. Thus, kerosene fuels are more practical for many uses.

RP-1 is most commonly burned with LOX (liquid oxygen) as the oxidizer, though other oxidizers have also been used. RP-1 is a fuel in the first-stage boosters of the Soyuz-FG, Zenit, Delta I-III, Atlas, Falcon 9, Antares and Tronador II rockets. It also powered the first stages of the Energia, Titan I, Saturn I and IB, and Saturn V. ISRO is also developing a RP-1 fueled engine for its future rockets.[2]

During and immediately after World War II, alcohols (primarily ethanol, occasionally methanol) were the single most common fuel for large liquid-fueled rockets. Its high heat of vaporization kept regeneratively cooled engines from melting, especially considering that alcohols would typically contain several percent water. However, it was recognized that hydrocarbon fuels would increase engine efficiency, due to a slightly higher density, the lack of an oxygen atom in the fuel molecule, and negligible water content. Whatever hydrocarbon was chosen, though, would have to replicate alcohol's coolant ability.

Many early rockets had burned kerosene, but as burn times, combustion efficiencies, and combustion-chamber pressures grew, and as engine masses shrank, the engine temperatures became unmanageable. Raw kerosene used as coolant would dissociate and polymerize. Lightweight products in the form of gas bubbles, and heavy ones in the form of engine deposits, then blocked the narrow cooling passages. The coolant starvation raised temperatures further, accelerating breakdown. This cycle would escalate rapidly (i.e., thermal runaway would occur) until an engine wall ruptured.

This occurred even with the entire flow of kerosene used as coolant. Rocket designers turned to the fuel chemists to formulate a heat-resistant hydrocarbon. The specification was completed in the mid-1950s.

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de·fen·es·trate
dēˈfenəˌstrāt/
verb
  1. 1
    rare
    throw (someone) out of a window.
    "she had made up her mind that the woman had been defenestrated, although the official verdict had been suicide"
  2. 2
    informal
    remove or dismiss (someone) from a position of power or authority.
    "the overwhelming view is that he should be defenestrated before the next election"
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From Wikipedia, the free encyclopedia
 
 
Thorium,  90Th
Thorium sample 0.1g.jpg
General properties
Name, symbol thorium, Th
Appearance silvery, often with black tarnish
Pronunciation /ˈθɔəriəm/
thawr-ee-əm
Thorium in the periodic table
Hydrogen (diatomic nonmetal)
 
Helium (noble gas)
Lithium (alkali metal)
Beryllium (alkaline earth metal)
 
Boron (metalloid)
Carbon (polyatomic nonmetal)
Nitrogen (diatomic nonmetal)
Oxygen (diatomic nonmetal)
Fluorine (diatomic nonmetal)
Neon (noble gas)
Sodium (alkali metal)
Magnesium (alkaline earth metal)
 
Aluminium (post-transition metal)
Silicon (metalloid)
Phosphorus (polyatomic nonmetal)
Sulfur (polyatomic nonmetal)
Chlorine (diatomic nonmetal)
Argon (noble gas)
Potassium (alkali metal)
Calcium (alkaline earth metal)
 
Scandium (transition metal)
Titanium (transition metal)
Vanadium (transition metal)
Chromium (transition metal)
Manganese (transition metal)
Iron (transition metal)
Cobalt (transition metal)
Nickel (transition metal)
Copper (transition metal)
Zinc (transition metal)
Gallium (post-transition metal)
Germanium (metalloid)
Arsenic (metalloid)
Selenium (polyatomic nonmetal)
Bromine (diatomic nonmetal)
Krypton (noble gas)
Rubidium (alkali metal)
Strontium (alkaline earth metal)
   
Yttrium (transition metal)
Zirconium (transition metal)
Niobium (transition metal)
Molybdenum (transition metal)
Technetium (transition metal)
Ruthenium (transition metal)
Rhodium (transition metal)
Palladium (transition metal)
Silver (transition metal)
Cadmium (transition metal)
Indium (post-transition metal)
Tin (post-transition metal)
Antimony (metalloid)
Tellurium (metalloid)
Iodine (diatomic nonmetal)
Xenon (noble gas)
Caesium (alkali metal)
Barium (alkaline earth metal)
Lanthanum (lanthanide)
Cerium (lanthanide)
Praseodymium (lanthanide)
Neodymium (lanthanide)
Promethium (lanthanide)
Samarium (lanthanide)
Europium (lanthanide)
Gadolinium (lanthanide)
Terbium (lanthanide)
Dysprosium (lanthanide)
Holmium (lanthanide)
Erbium (lanthanide)
Thulium (lanthanide)
Ytterbium (lanthanide)
Lutetium (lanthanide)
Hafnium (transition metal)
Tantalum (transition metal)
Tungsten (transition metal)
Rhenium (transition metal)
Osmium (transition metal)
Iridium (transition metal)
Platinum (transition metal)
Gold (transition metal)
Mercury (transition metal)
Thallium (post-transition metal)
Lead (post-transition metal)
Bismuth (post-transition metal)
Polonium (post-transition metal)
Astatine (metalloid)
Radon (noble gas)
Francium (alkali metal)
Radium (alkaline earth metal)
Actinium (actinide)
Thorium (actinide)
Protactinium (actinide)
Uranium (actinide)
Neptunium (actinide)
Plutonium (actinide)
Americium (actinide)
Curium (actinide)
Berkelium (actinide)
Californium (actinide)
Einsteinium (actinide)
Fermium (actinide)
Mendelevium (actinide)
Nobelium (actinide)
Lawrencium (actinide)
Rutherfordium (transition metal)
Dubnium (transition metal)
Seaborgium (transition metal)
Bohrium (transition metal)
Hassium (transition metal)
Meitnerium (unknown chemical properties)
Darmstadtium (unknown chemical properties)
Roentgenium (unknown chemical properties)
Copernicium (transition metal)
Ununtrium (unknown chemical properties)
Flerovium (post-transition metal)
Ununpentium (unknown chemical properties)
Livermorium (unknown chemical properties)
Ununseptium (unknown chemical properties)
Ununoctium (unknown chemical properties)
Ce

Th

(Uqb)
actinium  thorium  protactinium
Atomic number (Z) 90
Group, block group n/a, f-block
Period period 7
Element category   actinide
Standard atomic weight (±) (Ar) 232.0377(4)[1]
Electron configuration [Rn] 6d2 7s2
per shell
2, 8, 18, 32, 18, 10, 2
Physical properties
Phase solid
Melting point 2023 K (1750 °C, 3182 °F)
Boiling point 5061 K (4788 °C, 8650 °F)
Density near r.t. 11.724 g/cm3
Heat of fusion 13.81 kJ/mol
Heat of vaporization 514 kJ/mol
Molar heat capacity 26.230 J/(mol·K)
vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 2633 2907 3248 3683 4259 5055
Atomic properties
Oxidation states 4, 3, 2, 1
Electronegativity Pauling scale: 1.3
Ionization energies 1st: 587 kJ/mol
2nd: 1110 kJ/mol
3rd: 1930 kJ/mol
Atomic radius empirical: 179.8 pm
Covalent radius 206±6 pm
Miscellanea
Crystal structure face-centered cubic (fcc)
Face-centered cubic crystal structure for thorium
Speed of soundthin rod 2490 m/s (at 20 °C)
Thermal expansion 11.0 µm/(m·K) (at 25 °C)
Thermal conductivity 54.0 W/(m·K)
Electrical resistivity 157 nΩ·m (at 0 °C)
Magnetic ordering paramagnetic[2]
Young's modulus 79 GPa
Shear modulus 31 GPa
Bulk modulus 54 GPa
Poisson ratio 0.27
Mohs hardness 3.0
Vickers hardness 295–685 MPa
Brinell hardness 390–1500 MPa
CAS Number 7440-29-1
History
Naming after Thor, the Norse god of thunder
Discovery Jöns Jakob Berzelius(1829)
Most stable isotopes of thorium
iso NA half-life DM DE(MeV) DP
227Th trace 18.68 d α 6.038
5.978
223Ra
228Th trace 1.9116 y α 5.520 224Ra
229Th trace 7340 y α 5.168 225Ra
230Th trace 75400 y α 4.770 226Ra
231Th trace 25.5 h β 0.39 231Pa
232Th 100% 1.405×1010 y α 4.083 228Ra
234Th trace 24.1 d β 0.27 234Pa
· references

Thorium is a chemical element with symbol Th and atomic number 90. A radioactive actinide metal, thorium is one of only two significantly radioactive elements that still occur naturally in large quantities as a primordial element (the other being uranium).[a]It was discovered in 1828 by the Norwegian priest and amateur mineralogist Morten Thrane Esmark[4] and identified by the Swedish chemist Jöns Jacob Berzelius, who named it after Thor, the Norse god of thunder.

A thorium atom has 90 protons and therefore 90 electrons, of which four are valence electrons. Thorium metal is silvery andtarnishes black when exposed to air. Thorium is weakly radioactive: all its known isotopes are unstable, with the seven naturally occurring ones (thorium-227, 228, 229, 230, 231, 232, and 234) having half-lives between 25.52 hours and 14.05 billion years. Thorium-232, which has 142 neutrons, is the most stable isotope of thorium and accounts for nearly all natural thorium, with the other five natural isotopes occurring only in traces: it decays very slowly through alpha decay to radium-228, starting a decay chain named the thorium series that ends at lead-208. Thorium is estimated to be about three to four times more abundant thanuranium in the Earth's crust, and is chiefly refined from monazite sands as a by-product of extracting rare earth metals.

Thorium was once commonly used as the light source in gas mantles and as an alloying material, but these applications have declined due to concerns about its radioactivity. Thorium is still widely used as an alloying element in TIG welding electrodes (at a rate of 1%-2% mix with tungsten).[5] It remains popular as a material in high-end optics and scientific instrumentation; thorium and uranium are the only significantly radioactive elements with major commercial applications that do not rely on their radioactivity. Thorium is predicted to be able to replace uranium as nuclear fuel in nuclear reactors, but only a few thorium reactors have yet been completed.

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Spoiler

 


Hydrazine

 

 

Hydrazine hydrate
Names
Systematic IUPAC name
Hydrazine[2]
Other names
Diamine;[1] Diazane;[2]Tetrahydridodinitrogen(N—N)
Identifiers
CAS Number
302-01-2 

3DMet
B00770
Beilstein Reference
878137
ChEBI
CHEBI:15571 

ChEMBL
ChEMBL1237174 

ChemSpider
8960 

EC Number
206-114-9
Gmelin Reference
190
Jmol interactive 3D
Image
KEGG
C05361 

MeSH
Hydrazine
PubChem
9321
RTECS number
MU7175000
UNII
27RFH0GB4R 

UN number
2029
InChI
*         InChI=1S/H4N2/c1-2/h1-2H2 

* Key: OAKJQQAXSVQMHS-UHFFFAOYSA-N 

*
*         InChI=1/H4N2/c1-2/h1-2H2 Key: OAKJQQAXSVQMHS-UHFFFAOYAZ
SMILES
*         NN
Properties
Chemical formula
N
2H
4
Molar mass
32.0452 g mol−1
Appearance
Colorless, fuming, oily liquid[3]
Odor
ammonia-like[3]
Density
1.021 g cm−3
Melting point
2 °C; 35 °F; 275 K
Boiling point
114 °C; 237 °F; 387 K
Solubility in water
miscible[3]
log P
0.67
Vapor pressure
1 kP (at 30.7 °C)
Acidity (pKa)
8.10[4]
Basicity (pKb)
5.90
Refractive index(nD)
1.46044 (at 22 °C)
Viscosity
0.876 cP
Structure
Molecular shape
Triangular pyramidal at N
Dipole moment
1.85 D[5]
Thermochemistry
Std molar
entropy (So298)
121.52 J K−1 mol−1
Std enthalpy of
formation (ΔfHo298)
50.63 kJ mol−1
Hazards
Safety data sheet
ICSC 0281
GHS pictograms

 

 

 

 

GHS signal word
DANGER
GHS hazard statements
H226, H301, H311, H314, H317, H331, H350, H410
GHS precautionary statements
P201, P261, P273, P280, P301+310, P305+351+338
EU classification(DSD)

 T+ 

 N [6]
R-phrases
R45, R10, R23/24/25, R34, R43, R50/53
S-phrases
S53, S45, S60, S61
NFPA 704

4
4
3
Flash point
52 °C (126 °F; 325 K)
Autoignition
temperature
24 to 270 °C (75 to 518 °F; 297 to 543 K)
Explosive limits
1.8–99.99%
Lethal dose or concentration (LD, LC):
LD50 (Median dose)
59–60 mg/kg (oral in rats, mice)[7]
LC50 (Median concentration)
260 ppm (rat, 4 hr)
630 ppm (rat, 1 hr)
570 ppm (rat, 4 hr)
252 ppm (mouse, 4 hr)[8]
US health exposure limits (NIOSH):
PEL (Permissible)
TWA 1 ppm (1.3 mg/m3) [skin][3]
REL (Recommended)
Ca C 0.03 ppm (0.04 mg/m3) [2-hour][3]
IDLH (Immediate danger
Ca [50 ppm][3]
Related compounds
Other anions
tetrafluorohydrazine
hydrogen peroxide
diphosphane
diphosphorus tetraiodide
Other cations
organic hydrazines
Related Binary azanes
Ammonia
triazane
Related compounds
diazene
triazene
tetrazene
diphosphene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

 verify (what is 


 ?)
Infobox references


Hydrazine is an inorganic compound with the chemical formula N 2H 4(also written H 2NNH 2). It is a colorless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. As of 2000, approximately 120,000 tons of hydrazine hydrate (corresponding to a 64% solution of hydrazine in water by weight) were manufactured worldwide per year.[9] Hydrazine is mainly used as a foaming agent in preparing polymer foams, but significant applications also include its uses as a precursor to polymerization catalysts and pharmaceuticals. Additionally, hydrazine is used in various rocket fuels and to prepare the gas precursors used in air bags. Hydrazine is used within both nuclear and conventional electrical power plant steam cycles as an oxygen scavenger to control concentrations of dissolved oxygen in an effort to reduce corrosion.

 

Contents
*         Molecular structure
    *         
*         Synthesis and production
    *         Oxidation by chloroamine from hypochlorite on ammonia
        *         
    *         Oxidation of urea by hypochlorite
        *         
    *         Oxidation by chloroamine from hypochlorite on ammonia in presence of acetone
        *         
    *         Oxidation by oxaziridine from peroxide on ammonia
        *         
*         Applications
    *         Main uses
        *         
    *         Precursor to pesticides and pharmaceuticals
        *         
    *         Small-scale, niche, and historic uses
        *         Rocket fuel
            *         
        *         Fuel cells
            *         
        *         Gun propellant
            *         
*         Reactivity
    *         Inorganic chemistry
        *         Acid-base behavior
            *         
        *         Redox reactions
            *         
        *         Hydrazinium salts
            *         
    *         Organic chemistry
        *         Hydrazone formation
            *         
        *         Wolff-Kishner reduction
            *         
        *         Heterocyclic chemistry
            *         
        *         Sulfonation
            *         
        *         Deprotection of phthalimides
            *         
    *         Biochemistry
        *         
*         Hazards
    *         
*         History
    *         
*         See also
    *         
*         References
    *         
*         External links
    *         


Molecular structure
Each H2N-N subunit is pyramidal in shape. The N-N single bond distance is 1.45 Å (145 pm), and the molecule adopts a gauche conformation.[10] The rotational barrier is twice that of ethane. These structural properties resemble those of gaseous hydrogen peroxide, which adopts a "skewed" anticlinal conformation, and also experiences a strong rotational barrier.

Synthesis and production
Different routes have been developed over the years:[9] the key step is the creation of the nitrogen-nitrogen single bond. In the Olin Raschig process, chlorine-based oxidants oxidize ammonia without the presence of ketone. In the peroxide process, hydrogen peroxide oxidizes ammonia in the presence of ketone. Instead of carbon-nitrogen double bond in imine, ureaprovides amine groups bonded to carbonyl for oxidation.

Oxidation by chloroamine from hypochlorite on ammonia
Hydrazine is produced in the Olin Raschig process from sodium hypochlorite (the active ingredient in many bleaches) and ammonia, a process announced in 1907. This method relies on the reaction of chloramine with ammonia to create the nitrogen-nitrogen single bond as well as a hydrogen chloride byproduct:[11]
NH2Cl + NH3 → H2N-NH2 + HCl

Oxidation of urea by hypochlorite
Related to the Raschig process, urea can be oxidized instead of ammonia. Again sodium hypochlorite serves as the oxidant. The net reaction is shown:[12]
(H2N)2C=O + NaOCl + 2 NaOH → N2H4 + H2O + NaCl + Na2CO3
The process generates significant byproducts and is mainly practiced in Asia.[9]

Oxidation by chloroamine from hypochlorite on ammonia in presence of acetone
The Bayer Ketazine Process is the predecessor to the peroxide process. It employs sodium hypochlorite as oxidant instead of hydrogen peroxide. Like all hypochlorite-based routes, this method suffers from the fact that it produces an equivalent of salt for each equivalent of hydrazine.[9]

Oxidation by oxaziridine from peroxide on ammonia
Hydrazine can be synthesized from ammonia and hydrogen peroxide in the peroxide process (sometimes called Pechiney-Ugine-Kuhlmann process, the Atofina–PCUK cycle, or ketazine process).[9] The net reaction follows:[13]
2 NH3 + H2O2 → H2N-NH2 + 2 H2O
In this route, hydrazine is produced in several steps from ammonia, hydrogen peroxide, and a ketone such as acetone or methylethyl ketone. The ketone and ammonia first condense to give the imine, which is oxidised by hydrogen peroxide to the oxaziridine, a three-membered ring containing carbon, oxygen, and nitrogen. Next, the oxaziridine gives the hydrazone by treatment with ammonia, a process creating the nitrogen-nitrogen single bond. This hydrazone condenses with one more equivalent of ketone; the resulting azine is hydrolyzed to give hydrazine and regenerate the ketone. Unlike the Olin Raschig Process, this approach does not produce a salt as a by-product.[14]

Main uses
The majority use of hydrazine is as a precursor to blowing agents. Specific compounds include azodicarbonamide and azobisisobutyronitrile, which yield 100-200 mL of gas per gram of precursor. In a related application, sodium azide, the gas-forming agent in air bags, is produced from hydrazine by reaction with sodium nitrite.[9]
Hydrazine is also used as a propellant on board space vehicles, and to both reduce the concentration of dissolved oxygen in and control pH of water used in large industrial boilers. The F-16 fighter jet uses hydrazine to fuel the aircraft's emergency power unit.[15]

Precursor to pesticides and pharmaceuticals
Hydrazine is a precursor to several pharmaceuticals and pesticides. Often these applications involve conversion of hydrazine to the heterocycles pyrazoles and pyridazines. Examples of commercialized bio-active hydrazine derivatives include 3-amino-1,2,4-triazole Cefazolin, Rizatriptan, Anastrozole, Fluconazole, Metazachlor Pyridazine, Metamitron Pyrazole, Metribuzin, Paclobutrazol, Diclobutrazole, Propiconazole, and Triadimefon.[9]

Fluconazole, synthesized using hydrazine, is an antifungalmedication.

Small-scale, niche, and historic uses

Rocket fuel

Anhydrous hydrazine being loaded into the MESSENGERspace probe. The technician is wearing a safety suit.
Hydrazine was first used during World War II as a component of the rocket fuel, in a 30% mix by weight with both a 57% methanolcontent (itself called M-Stoff) and 13% water, it was called C-Stoff,[16] for the Messerschmitt Me 163B (the first rocket-powered fighter plane), and hypergolic with the high test peroxide based T-Stoff oxidizer. Hydrazine used alone by the World War II Germans received the alternative name of B-Stoff, a designation also used later for the Brennstoffmethanol/water fuel for the V-2 missile.
Hydrazine is used as a low-power monopropellant for the maneuvering thrusters of spacecraft, and was used to power the Space Shuttle's auxiliary power units (APUs). In addition, monopropellant hydrazine-fueled rocket engines are often used in terminal descent of spacecraft. Such engines were used on the Viking program landers in the 1970s as well as the Phoenix lander and Curiosity rover which landed on Mars in May 2008 and August 2012, respectively.
In all hydrazine monopropellant engines, the hydrazine is passed by a catalyst such as iridium metal supported by high-surface-area alumina (aluminium oxide) or carbon nanofibers,[17] or more recently molybdenum nitride on alumina,[18] which causes it to decompose into ammonia, nitrogen gas, and hydrogen gas according to the following reactions:[19]
1. 3 N2H4 → 4 NH3 + N2
2. N2H4 → N2 + 2 H2
3. 4 NH3 + N2H4 → 3 N2 + 8 H2
Reactions 1 and 2 are extremely exothermic (the catalyst chamber can reach 800 °C in a matter of milliseconds,[17]) and they produce large volumes of hot gas from a small volume of liquid,[18] making hydrazine a fairly efficient thruster propellant with a vacuum specific impulse of about 220 seconds.[20] Reaction 3 is endothermic and so reduces the temperature of the products, but also produces a greater number of molecules. The catalyst structure affects the proportion of the NH3 that is dissociated in Reaction 3; a higher temperature is desirable for rocket thrusters, while more molecules are desirable when the reactions are intended to produce greater quantities of gas[citation needed].
Other variants of hydrazine that are used as rocket fuel are monomethylhydrazine, (CH3)NH(NH2) (also known as MMH), and unsymmetrical dimethylhydrazine, (CH3)2N(NH2) (also known as UDMH). These derivatives are used in two-component rocket fuels, often together with dinitrogen tetroxide, N2O4. These reactions are extremely exothermic, and the burning is also hypergolic, which means that it starts without any external ignition source.[21]
There are ongoing efforts to replace hydrazine along with other highly toxic substances from the aerospace industry. Promising alternatives include hydroxylammonium nitrate, 2-Dimethylaminoethylazide (DMAZ)[22] and energetic ionic liquids.[23]

Fuel cells
The Italian catalyst manufacturer Acta has proposed using hydrazine as an alternative to hydrogen in fuel cells. The chief benefit of using hydrazine is that it can produce over 200 mW/cm2 more than a similar hydrogen cell without the need to use expensive platinum catalysts.[24] As the fuel is liquid at room temperature, it can be handled and stored more easily than hydrogen. By storing the hydrazine in a tank full of a double-bonded carbon-oxygen carbonyl, the fuel reacts and forms a safe solid called hydrazone. By then flushing the tank with warm water, the liquid hydrazine hydrate is released. Hydrazine has a higher electromotive force of 1.56 V compared to 1.23 V for hydrogen. Hydrazine breaks down in the cell to form nitrogen and hydrogen which bonds with oxygen, releasing water.[24] Hydrazine was used in fuel cells manufactured by Allis-Chalmers Corp., including some that provided electric power in space satellites in the 1960s.

Gun propellant
A mixture of 63% hydrazine, 32% hydrazine nitrate and 5% water is a standard propellant for experimental bulk-loaded liquid propellant artillery. The propellant mixture above is one of the most predictable and stable, with a flat pressure profile during firing. Misfires are usually caused by inadequate ignition. The movement of the shell after a misignition causes a large bubble with a larger ignition surface area, and the greater rate of gas production causes very high pressure, sometimes including catastrophic tube failures (i.e. explosions).[25]

Reactivity


Inorganic chemistry


Acid-base behavior


Hydrazine forms a monohydrate that is more dense (1.032 g/cm3) than the anhydrous material. Hydrazine has basic (alkali) chemical properties comparable to those of ammonia. It is difficult to diprotonate:[26]
[N2H5]+ + H2O → [N2H6]2+ + OH− Kb = 8.4 x 10−16
with the values:[27]
Kb = 1.3 x 10−6
pKa = 8.1
(for ammonia Kb = 1.78 x 10−5)

Redox reactions
The heat of combustion of hydrazine in oxygen (air) is 1.941 x 107 J/kg (9345 BTU/lb).[28]
Hydrazine is a convenient reductant because the by-products are typically nitrogen gas and water. Thus, it is used as an antioxidant, an oxygen scavenger, and a corrosion inhibitor in water boilers and heating systems. It is also used to reduce metal salts and oxides to the pure metals in electroless nickel plating and plutonium extraction from nuclear reactor waste. Some colour photographic processes also use a weak solution of hydrazine as a stabilizing wash, as it scavenges dye coupler and unreacted silver halides. Hydrazine is the most common and effective reducing agent used to convert graphene oxide (GO) to reduced graphene oxide (rGO) via hydrothermal treatment.[29]

Hydrazinium salts
Hydrazine is converted to solid salts of hydrazinium cation (N2H5+) by treatment with mineral acids. A common salt is hydrazinium sulfate, [N2H5]HSO4, also called hydrazine sulfate.[30] Hydrazine sulfate was investigated as a treatment of cancer-induced cachexia, but proved ineffective.[31]

Organic chemistry
Hydrazines are part of many organic syntheses, often those of practical significance in pharmaceuticals (see applications section), as well as in textile dyes and in photography.[9]

Hydrazone formation
Illustrative of the condensation of hydrazine with a simple carbonyl is its reaction with propanone to give the diisopropylidene hydrazine (acetone azine). The latter reacts further with hydrazine to yield the hydrazone:[32]
2 (CH3)2CO + N2H4 → 2 H2O + [(CH3)2C=N]2
[(CH3)2C=N]2 + N2H4 → 2 (CH3)2C=NNH2
The propanone azine is an intermediate in the Atofina-PCUK process. Direct alkylation of hydrazines with alkyl halides in the presence of base yields alkyl-substituted hydrazines, but the reaction is typically inefficient due to poor control on level of substitution (same as in ordinary amines). The reduction of hydrazones to hydrazines present a clean way to produce 1,1-dialkylated hydrazines.
In a related reaction, 2-cyanopyridines react with hydrazine to form amide hydrazides, which can be converted using 1,2-diketones into triazines.

Wolff-Kishner reduction
Hydrazine is used in the Wolff-Kishner reduction, a reaction that transforms the carbonyl group of a ketone into a methylene bridge (or an aldehyde into a methyl group) via a hydrazone intermediate. The production of the highly stable dinitrogen from the hydrazine derivative helps to drive the reaction.

Heterocyclic chemistry
Being bifunctional, with two amines, hydrazine is a key building block for the preparation of many heterocyclic compounds via condensation with a range of difunctional electrophiles. With 2,4-pentanedione, it condenses to give the 3,5-dimethylpyrazole.[33] In the Einhorn-Brunner reaction hydrazines react with imides to give triazoles.

Sulfonation
Being a good nucleophile, N2H4 can attack sulfonyl halides and acyl halides.[34] The tosylhydrazine also forms hydrazones upon treatment with carbonyls.

Deprotection of phthalimides
Hydrazine is used to cleave N-alkylated phthalimide derivatives. This scission reaction allows phthalimide anion to be used as amine precursor in the Gabriel synthesis.[35]

Biochemistry
Hydrazine is the intermediate in the anaerobic oxidation of ammonia (anammox) process.[36] It is produced by some yeasts and the open ocean bacterium anammox (Brocadia anammoxidans).[37] The false morel produces the poison gyromitrinwhich is an organic derivative of hydrazine that is converted to monomethylhydrazine by metabolic processes. Even the most popular edible "button" mushroom Agaricus bisporus produces organic hydrazine derivatives, including agaritine, a hydrazine derivative of an amino acid, and gyromitrin.[38][39]

Hazards
Hydrazine is highly toxic and dangerously unstable in the anhydrous form. According to the U.S. Environmental Protection Agency:
Symptoms of acute (short-term) exposure to high levels of hydrazine may include irritation of the eyes, nose, and throat, dizziness, headache, nausea, pulmonary edema, seizures, coma in humans. Acute exposure can also damage the liver, kidneys, and central nervous system. The liquid is corrosive and may produce dermatitis from skin contact in humans and animals. Effects to the lungs, liver, spleen, and thyroid have been reported in animals chronically exposed to hydrazine via inhalation. Increased incidences of lung, nasal cavity, and liver tumors have been observed in rodents exposed to hydrazine.[40]
Limit tests for hydrazine in pharmaceuticals suggest that it should be in the low ppm range.[41] Hydrazine may also cause steatosis.[42] At least one human is known to have died after 6 months of sublethal exposure to hydrazine hydrate.[43]

History
The name "hydrazine" was coined by Emil Fischer in 1875; he was trying to produce organic compounds that consisted of mono-substituted hydrazine.[44] By 1887, Theodor Curtius had produced hydrazine sulfate by treating organic diazides with dilute sulfuric acid; however, he was unable to obtain pure hydrazine, despite repeated efforts.[45] Pure anhydrous hydrazine was first prepared by the Dutch chemist Lobry de Bruyn in 1895.[46]

 

 

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